Friends Have More DNA in Common than Strangers

Friends Have More DNA in Common than Strangers

People may unsuspectingly choose friends who have some DNA sequences in common with them, a new analysis finds.

Researchers compared gene variations between nearly 2,000 people who were not biologically related, and found that friends had more gene variations in common than strangers.

The study lends a possible scientific backing for the well-worn clichés, “We’re just like family,” or “Friends are the family you choose,” the researchers said.

“Humans are unique in that we create long-term connections with people of our species,” said Nicholas Christakis, a social scientist at Yale University involved in the study. “Why do we do that? Why do we make friends? Not only that, we prefer the company of people we resemble.”

The researchers did the study because they wanted “to provide a deep evolutionary account of the origins and significance of friendship,” Christakis said.

The new study is based on data from the Framingham Heart Study, which is a large, ongoing study looking at heart disease risk factors in the people living in one town: Framingham, Massachusetts. The researchers looked at data on people’s DNA, as well as who was friends with whom.

After analyzing almost 1.5 million markers of gene variations, the researchers found that pairs of friends had the same level of genetic relation as people did with a fourth cousin, or a great-great-great grandfather, which translates to about 1 percent of the human genome.

The most common gene shared by friends was the “olfactory” gene, which is involved in a person’s sense of smell.

Although 1 percent may not sound like much, Christakis said in a statement, “to geneticists it is a significant number.

The article is interesting and I mostly agree, except “Humans are unique in that we create long-term connections with people of our species”. We are not unique in creating long term connections with other members of our species. Long term friendships exist in social creatures like chimps, dolphins, and many others, though they may be more closely connected genetically. We even have evidence of cross species long term friendships, such a an elephant and dog at the Hohenwald, Tenn. nature sanctuary.

I’m far from an expert in these matters but it seems to me that sampling could play a part. Friends from small, close-knit communities would seem likely to come from similar genetic stock when compared against someone, say, from another part of the country.

I can see many ways in which this could work for example I teach Technology (among other subjects) a significant number are pretty far along the autistic spectrum. There is most likely a genetic cause for this as it tends to be more common in families. So we could say that there is a genetic link to computer literacy. It seems to me there could be a similar effect in people for example who are very sporty may well share genes that dictate say, testosterone levels this may well have genetic markers. So your testicles could be choosing your friends for you.

Of course it may be that we just can’t stand being around people who to our minds stink.